Variations in pain threshold, drug tolerance, and visceral sensitivity among patients make it difficult to anticipate the appropriate dose of sedation for gastrointestinal endoscopy. Propofol was recently introduced for sedation in endoscopy and has a rapid onset and offset of action, making it an ideal substance for patient-controlled administration. Several controlled trials have demonstrated that during colonoscopy, patient-controlled application of propofol alone or in combination with various opioids is effective,safe, and yields high patient satisfaction. Target-controlled infusion of propofol has shown encouraging results for prolonged upper endoscopy procedures like endoscopic retrograde cholangio pancreatography.